Nonslip screw driver and screwhead



J y 1954 J. LISSY NONSLIP SCREW DRIVER AND SCREWHEAD Filed June 21, 1951Patented July 2@, 1%54 ,d i tfi 1 Claim.

This invention relates to a non-slip screw driver and screw head.

It is an object of the present invention to provide a screw having aslot chute in such a manher that upon receiving a specially formed screwdriver and turning the screw driver slightly, there is no chance for thescrew driver to slip from the screw head and it is locked upon the screwhead.

Other objects of the invention are to provide a non-slip screw driverand screw head combination which is of simple construction, inexpensiveto manufacture, permits easy insertion of the screw driver into the slotwithin the head, makes possible the use of a standard. screw driverwithin the head if the special screw driver is not available at thetime, durable and efficient in use.

For other ohiects and for a better understandof the invention, referencemay be had to the following detailed description taken in connectionwith the accompanying drawing, in which:

Fig. 1 is collective and perspective View showing the end of the screwdriver and of a screw bolt having a head specially formed to receive thespecial screw driver.

Fig. 2 is transverse sectional view of the screw driver taken on line 22of Fig. 1.

Fig. 3 is a top plan view of the screw head and looking into the slotthereof.

Fig. 4 is a vertical elevational View of the screw driver fitted into ascrew head.

Fig. 5 is a top plan view of a screw head and of the screw driver turnedthereinto for grinning action, the view being taken on line 5ii of Fig.4.

Fig. 6 is a transverse se ti nal view taken on the same line as the viewof 5 is taken. but with the screw driver twisted out of engagement withthe sides of the slot and the undercut areas thereof.

7 shows a screw driver supporting a screw and held in a position toapply the screw to an under surface.

Referrin now to the figures. iii re resents the screw bolt havin a screwM with a special slot is cut according to the present invention. Thisslot iii has the sides thereof beveled away from the center. indicatedat is and M, undercut from the center at opposite locations. as indie. dat E5 and it.

A screw driver end it is provided on the opposite sides thereofpectively with downwardly and outwardly flared projections I! and i8adapted to fill respectively the undercut spaces i5 and iii of the walls13 and M of the slot is in the head H.

As the screw driver is turned after being put in the slot in the mannerillustrated in Fig. 5, this action is effected. It will be seen that itis impossible for the screw driver end to be removed from the slot inthe screw from any direction long as it is turned to the position shownin Fig. 5. It cannot slide either to the right or left through the slotnor can it be pulled axially without first being rotated or returned tothe position shown in Fig. 6.

While the invention is shown applied to a machine screw in Fig. 1, itwill he understood that it can be equally applied to a wood screw, asindicated at IS in Figs. to 7. The same type of slot as defined above isprovided in this wood screw.

As shown in Fig. '7, the screw driver 1! supports and retains a screw onits upper end with the screw driver being held in an inverted positionand in order that the screw It can be forced into the under surface of astructure indicated at 2 1.

When the non-slip screw driver is inserted into the non-slip screw headand when a slight turn is made to the right with the screw driver, thescrew driver tends to wedge itself into the undercut portions of thescrew head. This interlocking action of the screw driver with the screwhead keeps the screw driver from slipping to the right or to the left ofthe slot.

While various changes may be made in the detail construction. it shallbe understood that such. changes shall be within the spirit and scope ofthe present invention as defined by the appended claim.

Having thus set forth and disclosed the nature of my invention, what isclaimed is:

In combination, a screw head havin a transverse ton slot defin ngopposed side wall therein, said s ot be n widened. from. its centertoward both ends the top face of the screw head. two diagonally oppositeper one of the side walls of the slot being disposed. in planesextending parto the of the screw the other two diagonally oppositeportions of side walls of the slot being undercut from the top face ofthe screw head to the bottom of the slot, a screw driver ofsubstantially rectangular crosssection and having its faces taperedtowards the end of the screw driver, two diagonally opposed portions ofthe faces at the end portion of the driver having outwardly inclinedprojections at an angle complementary to that of the undercut portionsof the side walls of the slot in the screw head, so that the twodiagonally oppositely disposed projections engage the undercut walls ofthe screw head in operative position.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 132,946 Armstrong Nov. 12, 1872 685,197 Barnes Oct. 22, 19011,656,095 Groos Mar. 18, 1913 1,411,242 Faust Mar. 23, 1922 FOREIGNPATENTS lluinher Country Date 10,612 Germany Jan. 31, 1880

